Fuel injection valve

Abstract

In a fuel injection valve having a housing pipe, a valve movable reciprocatingly and axially inside the housing pipe, and a body valve having a bottom wall constituting a valve seat with which the valve comes in contact and a side wall whose axial end is connected to a circumferential periphery of the bottom wall and whose the other axial end is fitted to and heat bonded to an end of the housing pipe, the side wall is provided on an outer circumference thereof with a ring shaped groove that is formed in advance before the body valve and the housing pipe are heat bonded to each other and serves to prevent a deformation of the side wall due to heat generated by the heat bonding from being transmitted straight to the valve seat.

What is claimed is:  
     
       1. A fuel injection valve comprising: 
       a housing pipe;  
       a body valve movable reciprocatingly and axially inside the housing pipe; and  
       a body valve having a bottom wall constituting a valve seat with which the valve comes in contact and a side wall whose axial end is connected to a circumferential periphery of the bottom wall and the other axial end is fitted to and heat bonded to an end of the housing pipe, the side wall being provided midway between the axial end and the other axial end thereof with a recess that is formed in advance before the body valve and the housing pipe are heat bonded to each other and serves to prevent a deformation of the side wall due to heat generated by the heat bonding from being transmitted straight to the valve seat;  
       wherein at least a part of the side wall of the body valve is exposed outside of the housing pipe, and the recess is formed on the side wall of the exposed part of the body valve so that the recess is not covered by the housing pipe.  
     
     
       2. A fuel injection valve according to  claim 1 , wherein the recess is a ring shaped groove formed on an outer circumference of the side wall. 
     
     
       3. A fuel injection valve according to  claim 2 , wherein the ring shaped groove is located in a vicinity of a place where the body valve and the housing pipe are heat bonded to each other. 
     
     
       4. A fuel injection valve according to  claim 1 , wherein the heat bonding is performed by welding. 
     
     
       5. A fuel injection valve according to  claim 1 , further comprising an injection hole plate which is separate from the body valve. 
     
     
       6. A fuel injection valve according to  claim 5 , wherein the injection hole plate has generally a cup-shaped cross section and surrounds the side wall of the body valve located at an injection hole side. 
     
     
       7. A fuel injection valve according to  claim 6 , wherein the recess is formed between a top end of a part of the injection hole plate surrounding the side wall of the body valve and the end of the housing pipe heat bonded to the body valve.